This invention relates to interconnecting linkage for handcuffs.
Handcuffs, such as those shown in U.S. Pat. No. 2,390,885 to Kelley, typically have a pair of identical ring-like members interconnected by a chain or hinges. Each ring or cuff comprises two arcuate frame parts, known as a jaw and cheek, that are pivotally coupled to one another. A pawl-and-ratchet mechanism permits one-way rotational movement of the jaw as it pivots through the spaced apart arms or plates that form the cheek. Teeth on the pawl's underside ride over complimentary ratchet teeth in the top of the jaw, as the jaw rotates into the cheek, to lock the cuff around a person's wrist. Spring pressure atop the pawl is meant to prevent the jaw from backing off and unlocking the cuff.
Cuffs are supposed to restrict individuals, but present day criminals pose a problem. Many are drug users, and high when arrested. The drugs (e.g., heroin or crack) make them impervious to pain. When cuffed, addicts will often try to twist and break the cuffs' interconnecting linkage. Though rare, instances have occurred where a rush of adrenalin, coupled with a blockage to pain, have enabled a subdued felon to tear apart a pair of cuffs. The resulting surprise does not sit well with police, who rightfully expect cuffs to work.
Strength standards have been set by the National Institute of Justice ("NIJ"), which is part of the U.S. Department of Justice. According to Section 4.7 of NIJ Standard-0307.01 (1982), each pair of closed handcuffs must withstand a hanging weight of 495 pounds for a period of not less than 30 seconds. The cuffs shall not open under that load, shall show no sign of permanent distortion or fracture and shall function in a normal manner following this test.
Previous attempts have been made either to increase the strength of interconnecting linkages or to restrict the prisoner's ability to twist the linkage. For example, U.S. Pat. No. 4,300,368 to Sullivan discloses a pair of parallel, multi-link hinges for cuffs. They are designed to restrict flexion, rotation and adduction of the prisoner's hands and wrists. However, Sullivan's multi-link hinges are still subject to torsional breakage, though at a reduced risk. This especially occurs if the cuffs are applied to a prisoner's wrists in front of him (e.g., during long transport), instead of behind his back.
Sullivan was an improvement over basically a single-link hinge assembly, disclosed in Netherlands Pat. 6,808,902. While the Dutch hinge avoided the play or flexibility of chains, it had a problem. The assembly was too rigid and did not allow for any axial movement between the cuffs, either away or toward one another. Also, the stiff linkage prevented the cuffs from being folded totally upon one another. There was also a slight triangular shape, which made the cuffs cumbersome to pack (for shipping) and difficult to insert in a policemen's carrying pouch.
It is therefore a primary object of the present invention to provide an improved hinge assembly for handcuffs that overcomes the deficiencies of the prior art.
It is another general object to provide an improved hinge assembly that is superior in strength.
It is still another object to provide such an improved hinge assembly, with oversized pin slots, that permit full nesting of the cuffs, so that they can compactly sit flush against one another in a side-by-side arrangement.
It is a further object to provide an improved hinge assembly that is constructed to avoid tampering found in multi-linkage assemblies.
The above and other objects will become more readily apparent when the following descriptions are read in conjunction with the accompanying drawings.